Evidence that endogenous benzdiazepine-like compounds increase during spontaneous delivery

It has been established that endogenous benzodiazepines (EBDZ) play a role in the pathogenesis of different pathologies like hepatic encephalopathy or idiopathic recurring stupor(1-2). Evidences have not been provided about the role of EBDZ during pregnancy and delivery. In this work we evaluated a possible changes of EBDZ in maternal/foetal serum during delivery after spontaneous labour (VD) or caesarean section (CS). For both VD and CS groups (n=24) 3 blood samples were collected at 3 different times: the first was collected at least 3 days before labour and delivery, the second was collected at the moment of the delivery or at foetal abdominal extraction; the third sample was obtained at 2nd day post-partum. Determination of EBDZ was performed as already described (1) and cortisol was measured through commercially available radioimmunoassay kit. For the statistical analysis of EBDZ Wilcoxon test was used for within-subjects comparison and Mann-Whitney tests for between subjects comparison. For the statistical analysis of cortisol levels the analysis of variance and paired t-test was used. In the VD group a significant increase of EBDZ occurred at delivery respect with both baseline (P=0.008) and postpartum (P=0.028) values. Interestingly in CS group were found no differences in the 3 different analysed samples. The cortisol levels in VD group at delivery (560 ± 156 ng/ml) were found to be higher than that at baseline (252 ± 93, t= 5.47, P<0.0001) and post-partum (241 ± 44, t=6.11, P<0.0001) while in CS group no significant changes were found. These findings demonstrated for the first time that parturition is associated with a marked increase of EBDZ which could be attributed to stress present at delivery time.